A combined epidemiologic, cytogenetic and pathologic approach is sustained in the continuing study of early reproductive loss. A further series of cases (women having spontaneous abortions) and controls (women whose pregnancies continue beyond 28 weeks) will be recruited from one hospital. A new questionnaire will investigate intensively the effects of caffeine containing beverages (coffee, tea, colas and other soft drinks); further data relating to selected other exposures, at present under analysis, will be collected. Outcomes under study include spontaneous abortion of a chromosomally normal conceptus; conception of an aneuploid zygote; abortion of a morphologically abnormal conceptus; birthweight, gestation and viability among control births. A prospective study, with very early pregnancy loss as an endpoint of interest, will be developed. Maternal serum of selected cases will be tested for embryotoxicity using a bioassay system; blood specimens will be stored for future analysis.